In U.S. Pat. No. 4,394,597, issued July 19, 1983, in the name of J. A. Mas and assigned to the Allied Chemical Corporation, there is disclosed multiple pole, axial field electromagnetic devices such as motors and generators in which the rotor and/or stator are formed of cylindrical core elements of annular cross-section having radial slots adapted to receive windings and/or conductors therein. More particularly, in several embodiments of the invention set forth in such patent, the rotor structure set forth takes the form of a cylindrical member having a plurality of radially disposed slots which are cut entirely therethrough while the magnetic return path for the rotor is separately provided apart from the rotating structure thereof.
As the invention set forth in such patent envisions the use of certain magnetic materials in strip or ribbon form, and in any event, rotor structure is generally required to be laminated, it will be appreciated that the formation of flow-through rotors, i.e., those having a separate magnetic return path in an axial or radial field devices can be a costly and time-consuming process especially when the material employed in the formation of the laminated rotor structure is relatively thin.
This may be appreciated, for instance, upon a consideration of B. Litman U.S. Pat. No. 2,550,571 which is directed to an axial gap motor and illustrates, as shown in FIG. 4, rotor structure wherein a rotor spider is employed to support a squirrel cage secondary member forming the pancake-like rotor disclosed therein. Within the conductive squirrel cage is formed the magnetic flux carrying member which is made up of a plurality of discrete, spaced sets of radial stacked tooth punchings 25 which are completely or nearly completely magnetically disconnected from one another and act to carry flux in an axial direction. The costly and time-consuming process of establishing the radial stacked tooth punchings 25 within such a rotor can readily be envisioned.
While the strip-like materials considered in U.S. Pat. No. 4,394,597 may take the form of such conventional materials as silicon iron or the like, the application additionally envisions the use of amorphous metallic alloys such as those available from Allied Corporation under its Metglas trademark due to the manner in which the same markedly reduce hysteresis and eddy current losses as a result of the high electrical resistivity characteristics and the low coercivity manifested thereby. These materials are preferred since, in essence, when amorphous magnetic alloys of this type are employed in the axial field electromagnetic devices described in the aforementioned U.S. patent, resulting core losses exhibited tend to be approximately one-seventh of those present when conventional materials are utilized. However, such amorphous magnetic alloys are typically available only in the form of strips, tape or ribbon which are relatively thin and hence configuring the same into appropriate core configurations is generally a time-consuming costly process and this is especially true when flow-through rotor apparatus is considered.
Therefore, it is an object of this invention to provide methods of manufacturing rotor structures from strips or ribbons of magnetic material.
A further object of this invention is to provide flow-through rotor structures formed of strips or ribbons of magnetic material.
An additional object of this invention is to provide methods of manufacturing flow-through rotor apparatus from strips or ribbons of magnetic material.
Another object of the present invention is to provide squirrel cage, axial field rotor structure formed of strips or ribbons of magnetic material.
A further object of the present invention is to provide methods of making squirrel cage axial field rotor structure from strips of thin magnetic material.
Various other objects and advantages of the present invention will become clear from the following detailed description of an exemplary embodiment thereof, and the novel features will be particularly pointed out in connection with the claims appended hereto.